Forum Index
Jeep Horizons HomeLinksJeep Horizons Tech Write-upsJeep newsLand useContact

 Watched TopicsWatched Topics   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Jeep 4.0l Cold Air Cowl Vent Intake

Goto page 1, 2  Next
 
Post new topic   Reply to topic     Forum Index -> Projects & Reviews
View previous topic :: View next topic  
Author Message
macb
Member


Joined: 01 Feb 2004
Location: San Antonio, TX

PostPosted: Mon Feb 02, 2004 5:50 am    Post subject: Jeep 4.0l Cold Air Cowl Vent Intake Reply with quote

I had seen several different types of snorkels, liked several of them (the michigan jeeper hummer style being my favorite except for the $300+ pricetag) I also liked K9's snorkel but I don't see water over the hood hardly ever...so being the cheap jeeper that I am (and the wife's new practice of hiding the visa card) I decided what I wanted to do based on these simple ideas;

1. cooler air into the engine meant better performance.
2. I didn't want something that could be smashed on the rocks
3. I liked the idea of it being stealthy
4. I still needed to be able to ford 3 feet of water minimum
5. I had to be able to afford it by saving my lunch money!

And I had seen a write up on the web somewhere during my travels but there were no pictures (danged computers), so it was time to put on my engineering hat and figure this out. If you ARE going to be fording water over 4' deep then I suggest taking a look at K9's writeup concerning his very cool home built snorkel.

My jeep is drawing air from the cowl vent in front of the windshield. If I don't show it to you, you'd never know it was there. It's waterproof as long as I don't completely submerge the jeep up to the windshield (not very likely in San Antonio).

FINAL RESULT:


What you need:

Buy or 'obtain' the following:
1. Another factory Air Tube (goes from the throttle body to the factory air box) - I bought mine online from e-bay for $35 - get the air box too if you can - in case you jack up the old one or if you ever want to go back.
2. Two 2.5" PVC electrical box connectors with nut (the gray kind is fire rated), available at home depot electrical department. Test fit them to the tube ends to ensure a tight fit.
4. small piece of sheet metal (you will need a 6 inch x 5 inch piece)
5. one 2.5" metal plumbing joint sleeve (lose the rubber insert)
6. metal primer or paint (we don't want any rust)

Tools list:
1. 2.5" hole saw - bimetal.
2. a tube of silicone RTV
3. riveting tool, and rivets (duh)
4. standard hand tools
5. hack saw or pvc saw
6. tin snips or something to cut the sheet metal.
7. metal file
8. a set of drill bits and a drill
9. safety glasses (wear them!)
10. good set of gloves for working with sheet metal.

The steps:
First remove the factory air box and air tube. Give the factory air box a good cleaning (unless your purchase of an air tube came with an air box also) and we will modify this first so the RTV can dry. Carefully cut a 6 inch by 5 inch piece of sheet metal and then trim it so that if fits the end of the box to cover the old intake hole where the air horn was located. (safety first, where your gloves and glasses when working, you only get 2 eyes and sheet metal is sharp)

Test fit this onto the air box and if it looks good file the edges, give it a good layer of silicone of make it air tight and put it in place. Drill 8 to 10 holes and rivet the cover in place (I put 5 around the outer edge and then another 4 very close to the old air horn hole, then silicone over the rivets. Now set this aside so the RTV can set up.


Determine the location for the new intake hole on the engine side of the air box (under the exit tube hole in the top half of the box), by placing the one of the electrical box connector nuts INSIDE the box, it needs to have clearance for the air filter, fittings, clamps when it is mounted. Be very sure to check for alternator clearance as well! Measure it twice, cut once. Drill the hole for the new intake using the hole cutter (keep the center scrap piece for later). You may have to trim the threaded end of the connector to allow for a tight fit, I took inch off of mine with a hack saw. Trim the excess to allow for a smooth physical connection. RTV the nut and the connector where they will contact the box and then assemble and set aside to allow for the RTV to set up.


Remove the cowl from the vehicle. First remove the wiper blades by folding them away from the windshield. Pull the locking tabs from under the wiper blades. Pull the blade assembly straight away.

Remove the 4 screws along the top of the cowl, remove the 1 screw in the cowl vent.

Lift the hood, pull the rubber seal from top edge of the firewall, and remove the 2 cowl screws at each end of the firewall.

Put the hood back down and carefully lift the leading edge of the cowl, then pull the cowl clear. Notice the large drain under the center of the cowl, this is where the water drains when it enters the cowl, on the passenger side you will also see the fresh air intake for you're a/c unit.

Using the scrap plastic cut from the air box as a guide determine where you will be cutting the hole in the firewall for the air intake (now it gets FUN!) you want to be just left from the grounding screw in the firewall as you look at the screw head in the engine compartment and low enough to allow for clearance below the lip of the firewall and the ground screw. Also check inside the cowl for clearance of the electrical box connector nut (again you may have to trim back the length of the threaded end to allow for a tight fit when installing this connector). This is also a good time to create a little space by removing the wire loom clamps that hold the wiring harness in place (and in your way) and then releasing the connectors in the center of the firewall and relocating them under the metal ledge (be careful to not damage the connectors).

Measure it again and check for clearance again, you only get one shot at this one! now it is time to drill - no turning back!!!! Make your hole in the firewall, clean up the edges with a file, mask it and give it a couple coats of paint or primer to stop any rusting. Make sure you allow the primer to dry...this is why I used the quick drying spray type (watch your overspray and remember it sprays through the hole!). Test fit the connector and then RTV all the connection points and assemble.

Hole Crap! You just made a 2.5" hole in your firewall!!!
Take a break and let your heart rate come back down!

Re-install the lower half of the air box

Lets prepare the new intake tube. Cut off about inch to either side of the oil breather connection - there is a base where it joins the tube - I cut mine right at the ridge of that joint. Using the metal joint sleeve temporarily reassemble the now shorter tube and check for fit and clearance in the engine compartment. If you need to trim the air tubes for length and/or fit now is the time to do it. Disassemble the new tube and RTV the interior of the metal plumbing joint sleeve (remember to remove the rubber insert). RTV the inside edge of one of the tube halves. Use the joint sleeve to tightly join the 2 halves. Back together. I put mine back at the same angles by using the seam in the tube. Put the new tube aside and allow the RTV to set up.


Really take a break now to ensure all the RTV has set up before you begin making the mechanical connections.

Assemble the new short tube between the 2 new connectors you installed and tighten the band clamps. I found it helpful to remove the clamp keys to allow me to spin the clamps to more accessible positions. Assemble the filter and top of the air box. Assemble the air box to throttle body tube. Reverse the cowl removal procedures.

Double check all your clearances and do a tool check.

Start it up!

Did you remember to take PICS!

Final thoughts and testing...
1. I have run a garden hose full blast at the cowl vent with the engine running - no problem ... as long as the lower end of the vent is not blocked it will drain water super fast.
2. I might test an air scoop/air dam to see if it will affect highway performance. but on the trail I want all that cooler air going down the intake.
3. I would have mounted the connector closer to rear corner of the box
4. the size of all the tubing is just under 2.5 inches...considering that the stock air horn is only like 1.5 inches inner diameter I figured this is good.


please let me know of any other tips or suggestions, I will edit this post if I think of any.
_________________
The difference between Genius and Stupidity?
Genius has limits...
H2 Recovery Team and NO BLING Gear!

Back to top
View user's profile Send private message Visit poster's website
YellowX
Member


Joined: 06 Jan 2004
Location: Weare, NH

PostPosted: Mon Feb 02, 2004 6:14 am    Post subject: Reply with quote

GREAT writeup!

Thanks for sharing!
Back to top
View user's profile Send private message Visit poster's website AIM Address
PAJeeper
Member


Joined: 02 Jan 2004

PostPosted: Mon Feb 02, 2004 6:20 am    Post subject: Reply with quote

Excellent job of describing your method.

good mod
Back to top
View user's profile Send private message
macb
Member


Joined: 01 Feb 2004
Location: San Antonio, TX

PostPosted: Mon Feb 02, 2004 7:50 am    Post subject: Reply with quote

PAJeeper wrote:
Excellent job of describing your method.

good mod

you have a typo...you mispelled 'madness' as 'method'...a common mistake!
_________________
The difference between Genius and Stupidity?
Genius has limits...
H2 Recovery Team and NO BLING Gear!

Back to top
View user's profile Send private message Visit poster's website
kizer
The Link Meister
The Link Meister


Joined: 02 Jan 2004
Location: Marysville, North of Seattle

PostPosted: Mon Feb 02, 2004 1:22 pm    Post subject: Reply with quote

So your using the stock filter and just extending the intake pipe behind wall.

Ok, now lets see a writeup using a K&N filter Wink

Either way thats pretty darn cool.

Hey what happens when it rains really, really hard? Is the intake in a good spot so it cant suck in water?
_________________
Links4Jeeps.com
1600+ Write-ups, and more
My Writeups | My Heap
Back to top
View user's profile Send private message Visit poster's website
macb
Member


Joined: 01 Feb 2004
Location: San Antonio, TX

PostPosted: Mon Feb 02, 2004 1:33 pm    Post subject: Reply with quote

kizer wrote:
So your using the stock filter and just extending the intake pipe behind wall.

Ok, now lets see a writeup using a K&N filter Wink

Either way thats pretty darn cool.

Hey what happens when it rains really, really hard? Is the intake in a good spot so it cant suck in water?

you could use a flat K&N in it no problem since it is the stock box. and I have sat in rush hour traffic - pouring rain...no problem.
If you read the write up you'll see where I mentioned the garden hose on full test.

The area under the cowl is graded down towards the center with a huge drain in the middle of it. The intake comes through the wall several inches above this low point so the only way it would suck water in would be if the bottom was somehow plugged. (shouldn't be a problem if you do your after trail cleaning and inspection of the undercarriage - you do that DON'T YOU?) Wink
_________________
The difference between Genius and Stupidity?
Genius has limits...
H2 Recovery Team and NO BLING Gear!

Back to top
View user's profile Send private message Visit poster's website
kizer
The Link Meister
The Link Meister


Joined: 02 Jan 2004
Location: Marysville, North of Seattle

PostPosted: Mon Feb 02, 2004 10:30 pm    Post subject: Reply with quote

Ok, Ok I admit I missed the test using the garden hose. Wink

I was just trying to pick apart a cool idea. So far I cant think of anything other than the fear of cutting a hole in the wall.
_________________
Links4Jeeps.com
1600+ Write-ups, and more
My Writeups | My Heap
Back to top
View user's profile Send private message Visit poster's website
macb
Member


Joined: 01 Feb 2004
Location: San Antonio, TX

PostPosted: Tue Feb 03, 2004 5:19 am    Post subject: Reply with quote

kizer wrote:
the fear of cutting a hole in the wall.


Mr. Green

yes...that is the toughest part of this mod.
You should have seen the crowd when I started mounting my rocker guards and putting on the LEDs Shocked
_________________
The difference between Genius and Stupidity?
Genius has limits...
H2 Recovery Team and NO BLING Gear!

Back to top
View user's profile Send private message Visit poster's website
swamp boy
Cherokee Muderator
Cherokee Muderator


Joined: 01 Jan 2004
Location: New Orleans LA.

PostPosted: Tue Feb 03, 2004 6:40 am    Post subject: Reply with quote

Nice Job .. McGawb... Glad you made it to our little corner of the intraweb... Mr. Green
Good to have you aboard...
_________________
BONE STOCK
Unless you include the sawzall work..

Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
cajunwrangler
Member


Joined: 18 Aug 2004

PostPosted: Sun Aug 22, 2004 8:14 pm    Post subject: Reply with quote

i was asking about this on jeepforum.com and i was given a link to your writeup and good job on it too. i was wondering if you think there is enough room to leave the fresh air intake in place and work around it or not.

on another note i recognized your jeep there carl... i heard you had chopped the rear end off and i see you finished your striping. looks good. by the way this is james from the red creek trip back in feb... helped with my alternator after it died on the second pass of the water strip.
Back to top
View user's profile Send private message
macb
Member


Joined: 01 Feb 2004
Location: San Antonio, TX

PostPosted: Sun Aug 22, 2004 8:21 pm    Post subject: Reply with quote

cajunwrangler wrote:
i was wondering if you think there is enough room to leave the fresh air intake in place and work around it or not.

?
I dont get the question...work on the engine without removing it? it is easy to remove as needed...only 2 clamps hold it in place.
_________________
The difference between Genius and Stupidity?
Genius has limits...
H2 Recovery Team and NO BLING Gear!

Back to top
View user's profile Send private message Visit poster's website
cajunwrangler
Member


Joined: 18 Aug 2004

PostPosted: Tue Aug 24, 2004 1:02 am    Post subject: Reply with quote

the fresh air intake for ac/heater... triangular shape in middle against firewall in 98' TJ. i would like to be able to run my intake around it, but it looks as if that isnt a possibility. i was just wondering if there is any way to leave it in.
Back to top
View user's profile Send private message
macb
Member


Joined: 01 Feb 2004
Location: San Antonio, TX

PostPosted: Tue Aug 24, 2004 3:19 am    Post subject: Reply with quote

cajunwrangler wrote:
the fresh air intake for ac/heater... triangular shape in middle against firewall in 98' TJ. i would like to be able to run my intake around it, but it looks as if that isnt a possibility. i was just wondering if there is any way to leave it in.

oh, yea...mine is still there...that is not an intake - that is the cowl drain! The fresh air intake is actually inside the cowl...on the far passenger side of the cowl.

open her up and you will see what I mean, unless it is different on the 98...I couldn't tell you.

the intake runs into the firewall on the passenger side of the compartment so it does not interfere.
_________________
The difference between Genius and Stupidity?
Genius has limits...
H2 Recovery Team and NO BLING Gear!

Back to top
View user's profile Send private message Visit poster's website
Billy's89XJ
Member


Joined: 03 Jul 2004
Location: I'm the Charlie Browniest

PostPosted: Wed Aug 25, 2004 4:40 pm    Post subject: Reply with quote

Okay, now we need one for a XJ Very Happy
_________________
"GODZILLA" More than a Jeep, it's family!!
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address Yahoo Messenger MSN Messenger
cajunwrangler
Member


Joined: 18 Aug 2004

PostPosted: Thu Aug 26, 2004 4:58 pm    Post subject: Reply with quote

i dont have my camera with me or my jeep for that matter so no pictures avalable right now. i am doing a V8 swap in my tj right now and i was asking my buddy helping me about the part i am speaking of and he said it is for circulating fresh air for ac/heat... maybe he's wrong, i just dont want to cut something out that im not sure of what it is if you catch my drift.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic     Forum Index -> Projects & Reviews All times are GMT - 8 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Visit links4jeeps.com for write-ups, forums and clubs




Jeep®, Wrangler, Cherokee, Liberty and Grand Cherokee are copyrighted and trademarked to Chrysler LLC.
jeephorizons.com is not in any way associated with or endorsed by the Chrysler LLC.
All other content is copyright Jeep Horizons 2004-2008.
Tech write-ups Links Discussion board Land use News Site Map Terms of Use

Powered by phpBB © 2001, 2005 phpBB Group